| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.beam.sdk.transforms; |
| |
| import org.apache.beam.sdk.annotations.Experimental; |
| import org.apache.beam.sdk.expansion.ExternalTransformRegistrar; |
| import org.apache.beam.sdk.values.PInput; |
| import org.apache.beam.sdk.values.POutput; |
| |
| /** |
| * An interface for building a transform from an externally provided configuration. |
| * |
| * <p>Classes which implement this interface will be instantiated externally and require a zero-args |
| * constructor. The {@code buildExternal} method will be called with the configuration object as a |
| * parameter. |
| * |
| * <p>This builder needs to be registered alongside with a URN through {@link |
| * ExternalTransformRegistrar}. Note that the configuration requires setters for all configuration |
| * parameters, e.g. if there is a parameter "start", there should be a corresponding setter |
| * "setStart". |
| * |
| * @param <ConfigT> A configuration object which will be populated with the external configuration. |
| * @param <InputT> The input type of the externally configured PTransform. |
| * @param <OutputT> The output type of the externally configured PTransform. |
| */ |
| @Experimental |
| public interface ExternalTransformBuilder<ConfigT, InputT extends PInput, OutputT extends POutput> { |
| |
| /** Builds the transform after it has been configured. */ |
| PTransform<InputT, OutputT> buildExternal(ConfigT configuration); |
| } |